Other than sweating up my feet I can't say I've had much issue with this. I wear a thin shirt when hiking hard that doesn't hold much sweat and I just layer up over it when I get to the top (my layers are all synthetic, even my puffy) so a tiny bit of sweat on my back isn't much concern to me). In colder weather I'm typically using something like the attack pant which has hip vents and at snow on the ground temps I don't think I've ever sweated up those, then I use zip on/off base and puffy pants to layer up so I don't have to take boots off to add leg layers ever (taking them off to change socks if I want though). My feet getting cold in that stuff is another matter that I'm working on but the rest of me I've not had issue with.